Power actuator



POWER AGTUATOR Original Filed Dec; 21 1926 3 Sheets-Sheet 1 ATTORNE flllw s sheets-sheet 2 C. S. 'BRAGG ET AL POWER ACTUATOR Original Filed Dec Aug.. 22, 1933.

IZ @M5 MM/o C. S. BRAGG ET AL Aug. 22, 1933'.

POWER ACTUATOR original Filed Dee; 21, 192e :5 sheets-sheet 3 r 1NVENTO9 ATTRNE l lPatented Aug. 22, 1933 UNITED STATES PATENT OFFICE 1,923,181 POWER Ac'rUA'roa Substitutel for application Serial No. 156,222, December 21, 1926. lThis application October 1. 1931. Serial No. 566.303

y 2s claims. (criss-152) Our invention consists in the novel features hereinafter described, reference being had to the `accompanying drawings which illustrate one embodiment of the invention selected by us for purposes of illustration, and said invention is fully disclosed in the following description and claims.

In the operation of independently operable brake mechanisms of an automotive vehicle, or independently operable brake mechanisms of an automotive vehicle and a trailing vehicle or vehicles, in which a main power actuator is employed for operating one set or brake mechanisms under the control of operator .operated valve mechanism, and an'auxiliary power actuator or actuators are operatively connected with the main actuator and arranged to operate other brake mechanisms of the same vehicle or of a trailer, the main and auxiliary actuators being connected by suitable piping so as to be controlled by the valve mechanism of the main actuator, it sometimes happens, especially if the distance between the main and auxiliary actuator or actuators is considerable, that there is a lag or delay in the operation of the Aauxiliary actuator or actuators on account of the fact that the higher pressure fluid, for example, must traverse piping of considerable length from the main actuator to the auxiliary actuator before it can actuate the piston of an auxiliary actuator. In our former application for Letters Patent of the United States, tiled August 30', 1926, and given Serial No. 132,364, said application being abandoned and then refiled on October 1, 1931, as` application No. 566,305, We have shown and described an. arrangement for operating an auxiliary actuator provided with a single acting piston and having its own controlling valve mechanism associated therewith, by the operator operated valve mechanism of the main actuator, byinterposing in the pipe connections between the main and auxiliary actuators a iiuid pressure operated control device connected with the piston of the auxiliary actuator and having a movable part connected with the valve mechnxnsm of the auxiliary actuator, so that the variations in pressures within the cylinder of the main actuator effected by the operation of its operator operated valve mechanism will directlyeifect corresponding movements oi' the valve mechanism of the auxiliary actuator, admitting higher pressure iiuid directly thereto for the application oi' the brake mechanism operated thereby, and securing the Joint and simultaneous operation of the main' and auxiliary actuators without appreciable lag or delay in the operation of the latter.

Our presentinvention has for its object to provide means for controlling the valve mechanism of an auxiliary actuator having a double acting piston through a fluid .pressure operated device control, and operated by the operator operated valve mechanismy of a main actuator having a double acting piston, in order that the simultaneous operative movements oi the main and auxiliary double acting 'pistons can be obtained without any appreciable lag or delay: andL enabling the operator to simultaneouslyappiy allof the independently operable brake mechanisms equally, and to simultaneously and positively release said brake mechanisms. and other-A wise simultaneously control the main and au'xiliary actuators even though they may be widely separated and the connecting piping relatively long.

Our invention also comprises certain novel features of construction and combination of parts hereinafter fully described, and particularly pointed out in the claims` Referring to the drawings which illustrate one embodiment of our invention selected by us for purposes of illustration,

Figure 1 represents dlagrammatically an installation oir brake mechanism and actuating means therefor in an automotive vehicle and trailer propelled thereby, and embodying our invention;

Figure 2 is an enlarged view in elevation lshowing the main actuator and the auxiliary actuator illustrated in Figure 1, and their pipe connections, portions of which are broken away;

Figure 3 is an enlarged sectional lview of lone form of main actuator which we preferably employ in carrying out our invention, and which is provided with a double acting piston;

Figureiisanenlargedsectionalviewofan auxiliary. actuator provided with a doubleacting piston and having its own controlling valve mechanism, and a uid pressure operated device operatively connected therewith and with the main actuator; and

Figure 5 isan enlarged sectional view o! the pressure actuated device illustrated in Figure 4.

In Figure l, the main or propelling vehicle indicated at A, by dotted lines. is provided with an internal combustion engine for propelling it, indicated at 60. having a carburetor 61 and suction passage 62 extending therefrom to the cylinders and including a manifold 83, the suction passage being provided with the usual throttle 2 y valve, at e4. The main vehicle is also provided withsuitable brake m which may -be applied to two or more of its supporting wheels, and which may be oi'- anv desired char- .'5acter. InFlgureLwehaveindicatedbrake ated by suction and atmospheric pressure, as thelow and high pressure mediums, and we have illustrated as the preferred form of said main actuator, a double acting power actuator con-A structed as shown in our United States Letters Patent N0. 1,826,415, dated October 6, 1931. 'I'he particularconstruction of the power actuator and forms no part of our present invention and is not speciiicalLv claimed hereimand will only be described insofar as it is n to an understanding of our present invention.

The main power actuator is illustrated in section ti Figure 3. and comprises a cylinder 1 closed at both ends by heads 2, a double acting piston 3 and controlling valve m located prei'- erably in the hub of the piston. The piston-is provided with oppositely extending piston rods 5 and 5*, extendmg through-stuffing boxes in the opposite heads, one of the piston rods, in this in. stance the piston rod 5, being connected by'a link 78 with the arm 'I7 for operating the .brake mechanism of the main vehicle, as shown in Figure 1. The piston 3 is provided with a suction chamber i7. in its hub and with valve chambers bers, and each'containing twooppositely disposed valves,.said valves being indicated at 40, of which 4l and 42 are the suction valves, while 40 and 43 45. are the air inlet valves. Interposed between the valves of each pair are yielding devices indicat- `ed at'50,'no rmaliy tending to seat them, The valves are preferably made of molded rubber or other suitable material having central openings 8381118 the sleeve so as to make a tight joint while permitting the movement` of the sleeve therethrough. The valve actuating sleeve is provided with a collar to engage each valve in a direction to open it, and the construction is such that a movement of the sleeve in either direction will open one valve of each pair. The piston hub is also provided with ports 34 and 35 for connect'- ing each valve chamber with the cylinder on one side of the piston. The valve mechanism is also connected with a source of suction, as the intake manifold of the internal .combustion engine, and with the atmosphere. In this instance the valve sleeve is shown provided with a plug 21, forward oi' which (at the left in Figure 3) are apertures 22 connecting the interior with the suction chamber 17, and the outer end of the valve sleeve is provided with a ntting 23 connected by a suction pipe `05,. a portion of which is exible, with the intake manifold oi the engine-between the throttle valve and the cylinders. This tting is also provided with an r 24 for connecting it by means of a link'lilwiththepedailever,orotheroperator with a main power actuator adapted to be oper- Y the operator operated valve mechanism `thereof- 11 and 12 located on opposite sides-of said chamwhich engage a longitudinally movable valve ac--gi tuating sleeve 20 extending through b'oth piston rods and the hub of the piston, the valves enoperated means, provided with the usual retracting'spring 89. Thevalve actuating sleeve 20 is also provided. with a Ystop collar 25 adjustable thereon and adapted to engage the adjacent head ofthe cylinder, so as to hold the suction valves 41 and 42 in open position when the piston is in.

retracted position, -as shown in Figure 3, thus connecting the cylinder on both sides of the piston with the suction pipe 65 and maintaining the piston normally submerged in vacuum.

Atmospheric air can be admitted to the cylinder on either side of the piston under the control of the valves and 43', the air entering through suitable apertures at the. outer ends of the piston rods 5 and 5 at the points indicated at 26 and 27. the apertre`2'lbeing provided with an air strainer 2'?l to exclude dust, and the valve sleeve is also preferably provided with apertures indicated at 28, in the -rear o f the plug 2-1, to .facilitate the admission of air to the valve 43. Means are also preferably provided for connecting the foot lever withthe brake mechanism operated by the actuator, and containing sil provision for sufiicient lost motion to secure the proper operation of the valves, so that when this lost motion is taken up the physicalforce of the operator can be-applied to the piston and the brakemechanism connected therewith, to positively actuate the brake mechanism in case of failure of power. In this instance the valve actuating sleeve 20 is shown provided with a collar indicated at 29 located between the outer" wall of the recess in a cap 30 secured to the piston` rod 5 and an inwardly extending collar ortiange 31- secured to said piston roo..

The suction pipe 651s preferably provided with anadjustable restricting valve '60 (see Figure 1) for restricting the passageof airv into the intake manifold, and with a'check valve 67 for within the actuator cylinder andsuction pipe the maximum ratification obtained in the manifold. Y i

In diagrammatic view, Figurev 1-, we have shown independently operable brake mechanisms,

EL F,'for any set oi' wheels, to be propelled by theinternal combustion engine-60.. which brake mechanisms are shown located at a considerable vdistance from the main brake mechanisms D. and C tuator. In the present instance we have shown the auxiliary brake mechanisms and auxiliary :nain vehicle.. Itis also to be understood, that 'while we have only shown in Figure. 1 a-main ve` hicle and a single trailer, the apparatus shown inconnection withthe trailer can be duplicated on other trailers, the auxiliary actuators of which can all be simultaneously operated from the main or master actuator by extending the connecting pipe lines. i

The auxiliary brake mechanisms may be of any desired kind, and may be applied to as many and operatively connected with an auxiliary ac- Y wheels as desired. For purposes of illustration we have shown the brake mechanisms, E, F, constructed and connected for joint operation in the same manner as the brake mechanisms of the main vehicle, the corresponding parts on the trailer being given the same numerals with the addition of the letter a and these parts need not be again described.

The auxiliary actuator is illustrated in section in Figure 4, and comprises a cylinder 101 closed at both ends by heads 102 and provided witha double acting piston 103, the hub of'which: lis

vprovided with the suction chamber 117, valve the main actuator.

, this instance extends beyond the head of the cylinder and is provided with a fluid pressure oper-` ated device hereinafter described, the said device being provided in this instance by an air inlet 126 provided with an air strainer 126. 120 represents the valve actuating sleeve which extends through the pressure operated device, through the hollow piston rod 105*l and the piston hub and said suction and air inlet valves, and is provided with a plug 121 adjacent to its inner end and with apertures 122 connecting its interior with the suction chamber 117. The exterior portion of the valve actuating sleeve 120 is provided with a tting 123 connected by a pipe 165, having a ilexible portion, with the suction pipe leading to the intake manifold. The valve actuating sleeve 120 is also provided with collars for engaging the valves in a direction `to open them, so that a movement of the sleeve in either direction will open one valve of each pair in the same manner as the valves of the main actuator are operated. In this instance, the said collars for the suction valves 141 and 142 are so located'that these valves as well as the air inlet valves 140 and 143 all remain seated, as shown in Figure 4, when the apparatus is in the normal position and the piston is retracted. It will be understood that the piston rod 105 is connected by alink 78y with the arm 77* in the rock shaft 76a of the trailer brake mechanism, as shown in Figure. 1.

\ The pressure operated control device comprises preferably a central body portion 90 of circular form recessed on its opposite faces and provided with exterior clamping plates 90 and 90b secured thereto by bolts or screws, so as to form two diaphragm chambers on opposite'sides of the central portion 90 through each of which extends a diaphragm 91 and 91, respectively, the outer edges of which are clamped between the central portion 90 and one of said plates 90* and 90. The plate 90h is provided with a hub portion 90c which is screwed upon or otherwise secured to the outer end-of the hollow piston rod 105', thus supporting the entire device upon and for movement with said piston rod. 'Ihe valve actuating sleeve extends through packing sleeve 90e in the central portion and clamping plates of the fluid pressure operated device, and is movable longitudinally therethrough. Said sleeve also extends through central apertures in. each ofv the diaphragms, but is provided with clamping nuts on opposite sides of each diaphragm, as indicated at 90, so that the central portions o f the diaphragms move with the ,sleeve 120.V The diaphragm 91 on the outer face of the central portion 90, at the left in Figures 4 and 5, divides that diaphragm chamber into two chambers 92 and 93. 'I'he exterior chamber 92 is connected by means of a pipe '97 with the cylinder of the main actuator on the forward side of the piston thereof. at the left in all the gures. The chamber 93 is connected by means of apassage 94 in the central portion or body 90 and by a flexible pipe 95 with the cylinder 101 of the auxillary'actuator on theforward side of the piston 103 therein. 'I'he diaphragm 91 is also provided with an aperture indicated at 96, which is normally closed by a check valve 96'l opening in a direction toward the chamber 972, and which may be formed by a piece of leather, rubber, or other flexible material, or otherwise From this construction it will be seen, that air may be withdrawnfrom theV auxiliary cylinder 101 forward of the piston through the pipe 95, passage 94, aperture 96 and pipe 97 to the forward end 0L the main actuator cylinder, lbut it cannot flow in the opposite direction. The chamber on the rear face of the `body portion 90 of the fluid pressure operated device is divided by the diaphragm 91n into two chambers 92* and 93e. Ihe chamber 92m is connected by a pipe 98 with the cylinder 1 of the vmain actuator in rear of the piston therein, while the chamber 93* is connected by a passage 94n in the central portion 90 oi! the pressure operated device and by a pipe 99, having' exible portions, with the cylinder 101 of the auxiliary actuator inV rear of the piston therein. The diaphragm 91a is also provided with a small aperture indicated at 96h, closed by -a check valve 96" shown as a ilap valve, so arranged that air may be withdrawn from the auxiliary actuator cylinder 101 through the pipe 99, passage 94, aperture 96h and the pipe 98 tothe corresponding end of the main actuator cylinder 1, bu't is not permitted to flow in the opposite direction.

Where more than one trailer is employed, the suction pipe 165 and the connecting pipes 97 and 98 may be provided with extensionsl indicated at 165, 97'l and 98, respectively, and broken away in Figure 1, extending to a similarly constructed auxiliary actuator on another trailer, etc., said pipes being preferably provided with cut-olf valves indicated at 165b, 97b and 98h, which can be closed when no additional trailer is employed. In like manner the suction pipe 65 and connecting pipes 97 and 98 may also be provided with cut-ofi valves indicated at 265, 297'and-298 in Figure 1', which can be closed when the trailer `indicated at B is not employed, in which case the main actuator will be operated to control the brake mechanism of the main vehicle only. It

will also be understood that the pipes 165, 97 and 98 will be provided with suitable exible portions indicated at 3 65, 397 and 398, extending from the main vehicle to the trailer to compensatethe slight relative movements of the two vehicles.

Assuming that the parts are arranged as shown in the drawings and as previously described, when the internal combustion engine is in operation and the vthrottle valve closed or partially closed, the air will be-exhausted from the main actuator cylinder on both sides of the piston through, the suction pipe 65 and the air will also lbe exhausted from both ends oi' the auxiliary actuator cylinder through l `the pipes wand 9 8. which communicate with the corresponding ends of the auxiliary actuator cylinder in the manner previousLv described through' the openings 96 and 96" in the respective dlaphragms o the prese sure actuated device. thus maintaining both the main piston and 'the auxiliary piston submerged inv vacuum. Obviously to operate the pistons it is only n to admit air at atmospheric pressurefin rear of said pistons, which will produce the forward movement of each piston without admitting any appreciable air to the intake manifold, thus preventing the liability of stalling the engine if idling, or otherwise interfering with its operation. If the operator desires to ap- Ythrough the pipe 98 to the chamber 92B of the uid pressure operated devicefclosing the flap valve 96 in the diaphragm 91* and flexing the diaphragm in the direction of the arrow in Figures 4 and 5, thereby moving the sleeve 120 in the direction of the arrow, and opening the suction valve 141 and the air inletvvalve 143 of the auxiliary actuator. Pressures remaining equal on both sides of diaphragm 91, said diaphragm offers no resistance to the movement of diaphragm 91. This instantly admits air at atmospheric pressure in rear of the piston 103 through the 'air cleaner 127 and the air inlet 12'7, and connects the cylinder 101 forward of the piston with the suction pipe 165 through the valve actuating sleeve 120, so that the piston 103 immediately moves forward substantially simultaneously with the movement of the main actuator piston, each actuator piston operating under the control of its own valve mechanism, the valve mechanism oi' the auxiliary actuator being controlled by the operator operated valve mechanism of the main actuator throughthe uid pressure operat- Ved device previously described. It will be seen that the atmospheric'air which operates the auxiliary piston instead of having to enter the main actuator cylinder and be transmitted through intervening pipe connections to the auxiliary cylinder enters the auxiliary actuator cylinder directly, thus obviating any lag in the operation of the auxiliary actuator, which would otherwise be likely to occur. Approximately equal presg sures will be exerted on the main and auxiliary pistons tending to move them simultaneously forward as long as the operator continues to advance the foot lever and the valve actuating sleeve 20 of the main actuator, thus simultaneously and equally applying the brake mechanisms connected with said pistons, which as before stated may be separate brake mechanisms of the same vehicle, or brake mechanisms of `different vehicles, as a main vehicle and trailer. As soon as the forward movement of theoperators foot ceases, the continued forward movement of the main actuator piston3 will move it forward slightly with respect to said sleeve, permitting 'the air inlet valve 43 to close This stops the forward movement of the main actuator piston, holding the brakes controlled thereby applied. As soon as the main actuator air inlet valve 43 closes, the slightest continued admission of air into the cylinder 101 in rear of the piston will equalize pressures in chambers 92l and 93*` on opposite sides of the diaphragm 91", and permit the sleeve 120 to move in a direction opposite to that of the arrow, Figure 4, with respect to the piston103 under the tension of the compressed springs 150, thus closing the inlet valve 143 and holding the brakes controlled by the auxiliary actuator as applied with a pressure equal to that .of the master or main cylinders.

The operator can release the atmospheric pressures in both cylinders and permit both sets of v brake mechanisms to relieve themselves by slightly releasing his pressure on the pedal of the main actuator, which will again permit the suction valve 42 to open, and permit an equalization of pressures in the main actuator cylinder through the suction valves 41 and 42, connecting the main actuator cylinder on both sides of the piston with the suction chamber. The consequent reduction of pressure in the main actuator cylinder in rear of the piston will be instantly transmitted to the chamber 92*A in rear of the diaphragm 91a through the pipe 98, and if the differences in pressure on opposite sides of this diaphragmy are suili'icientlygreat, will also flex the diaphragm in the direction opposite that indicated by the arrow in Figures 4 and 5, slightly opening this suction valve 142 and the air inlet valve 140 and producing corresponding equalization of pressures within the auxiliary actuator cylinder 101 and permitting both sets .of brakes to relieve themselves to the same extent. When the pressures are equalized on the opposite sides of the diaphragms 91 and 91, the auxiliary actuator valves will be returned by the springs 150 to the closed position, and the operator can instantly reapply the brakes, where repeated applications are desired, by again pressing the pedal lever forward.

- When the operator desires to return the brakes and the pistons to normal or retracted position, he will remove his 'foot from the pedal lever, allowing it to be retracted by its spring 89, shifting the valve actuating sleeve in a direction opposite to that indicated by the arrow in Figure 3, further opening the suction valve 42, closing the suction valve 41 and opening the air inlet valve 40 to admit air at atmospheric pressure to the main actuator cylinder forward of the piston, while connecting the cylinder in rear of the piston with the suction pipe. The increase in pressure on the forward side of the piston of the main actuator will bevcommunicated through the pipe 97 to the chamber 92 on the forward side of the diaphragm 91, closing the ilap valve 96'- and flexing the diaphragm 91 in a direction` opposite that of the arrow in Figure 4, thereby shifting the sleeve 120 rearwardly and opening the suction valve 142 and the air inlet valve 140. Simultaneously 'the reduction of pressure in the rear of the vmain actuator cylinder is accompanied..

by means of pipe 98, with acorrespondlng reduction in pressure in the chamber 92, which will cause diaphragm 91n also to flex in a direction opposite to that of the arrow until the pressures within the chambers 93*l and 93l are equalized through the passage 96h. This connects the auxiliary cylinder 101 in rear of the piston with the suction pipe 165 through the suction chamber-l 117 and the sleeve 120, and admits air to the cylinder on the forward side of the piston through `the air nuet 12s and the houowV piston rod1o5.

Both pistons, therefore, will be returned to their retracted or normal positions, shown in Figures j and partially closing thesuctionvalve 42 which still remains slightly open, thusequalizing the pressures in the cylinder on opposite sides of the piston, and connecting the cylinder on both sides of the piston with the suction pipe 65.

Chamber 92 is then in communication with the suction e through the pipe9'1, while chamber 93 is connected with the higher or atmospheric pressure forward of the piston in the auxiliary actuator cylinder by pipe,95, and the chambers 92 and 93 are in communication with each other through the passage 96. The diaphragm 91 will be returned to the normal position, closing suction valve 142 and air inlet valve 140 by the higher pressure in chamber 93. which cannot be instantaneously equalized with chamber 92 through the limited opening of the passage 96, but after the diaphragm and valves are returned to the neutral or closed position the air remaining in the auxiliary cylinder forward of the piston will be withdrawn through the passage 96 and through the main cylinder forward of the piston, while the auxiliary cylinder in rear of the piston is in communication with suction through pipe 99, chambers 92 and 93, aperture 96",-pipe 98 and theportion of the main cylinder in rear of the piston, the parts being restored to the original positions indicated in Figures 3 and 4.

It will thus be seen that both the main and auxiliary cylinders are maintained in an ex- .'iausted condition on both sides of the pistons ;herein, when the pistons are in retracted posizion, or, in other words, the pistons are submerged n vacuum, The operation of the operator con- ;rolled valve mechanism of the main actuator in L direction to apply the brakes effects the adnission of air directly to the main actuator cylnder in rear of the piston accompanied by the nstantaneous operation of the valve mechanism f the auxiliary actuator, to admit air directly `rom the atmosphere into the auxiliary actuator :ylinder in rear of its piston, and eiecting the ubstantially simultaneous and substantially `qual operation of both pistons to apply the lrakes connected therewith with substantially qual pressures, and without admitting any aplreciable quantity of air from either cylinder orward of the piston to the intake manifold of he engine, the operation of both pistons being nder the single control of the operator operated art or foot lever 88. The pressures in both acuator cylinders may be equalized substantially lmultaneously to permit the brakes to relieve aemselves, the brakes may be substantially siiultaneously reapplied and released and reaplied as often as necessary, as in traflic or on a ng down grade, all under the single control of 1e operator operated part, and by releasing the perator operated part and permitting it to be reacted by its spring, both pistons will be simul- |.neously restored by power to retracted posi'- on, together with brake mechanisms, and when l retracted position, the main and auxiliary aclator cylinders .will be again connected with the urce of suction on 4both sides of the piston in ich cylinder, to equalize pressures and again ibmerge the pistons in vacuum.

It will thus be seen that the usual lag in the eration of the auxiliary actuator or actuators,

hich would necessarily result if the atmospheric r or other higher pressure uid for operatg the auxiliary actuator piston had to pass .rough the pipe connections from the main or aster actuator cylinder, is avoided. It will also s seen that a standard sized main actuator may i used singly or to operate one or more auxiliary tuators without the necessity of increasing eier the areas of the passages or the valves, which mld be necessary if the air required to operate le or morel auxiliary actuators had to pass rough the main actuator cylinder. The diaphragms of the pressure actuated device are practically instantly responsive to variations in pressures in the master cylinder, and by operating the independent valve mechanism of the auxiliary actuator effect a practically simultaneous operation of the main and auxiliary pistons. It will also be noted that each diaphragm chamber is provided with a by-pass, herein shown in the vform of the apertures 96 and 96b formed in the diaphragms themselves, (but which need not necessarily be in the diaphragms), which by-passes serve to connect the chambers on the opposite side of each diaphragm with each other, and connect the auxiliary cylinder on both sides oi' the piston with the corresponding portion of the main cylinder and therethroughwith the intake manifold, through the partly opened suction valves 41 and 42 thereof, whenthe pistons are in retracted position, while theA said by-passes are provided with valves, in this instance the ap valves 96 and 96. which instantly close the respective by-passes whenever the pressure is to be exerted upon one or the other of said diaphragms in a direction to operate theI independent valve mechanism of the auxiliary actuator. After the piston of the main actuator cylinder has returned to its normal or off position and the controlling valve mechanism for the auxiliary actuator has returned to its neutral or normal position, these by-passes and check valves exhaust any air remaining in either end of the auxiliary cylinder, which air has not suilicient pressure to ex either of the diaphragms and which might retard the proper operation ofthe auxiliary actuator piston.

It will also be noted that by reason of the connection between the valve actuating sleeve of the main actuator and the main actuator piston, effected by the collar 29 and the ilange 31, before described, which provide a sufllcient amount of lost motion to allow the controlling valves oi!l the main actuator to be operated, the operator can add his physical power to that of the main actuator in the application of the brake 'mechanism connected with the main actuator, and it will also be understood that if the power fails for any reason, the operator can by depressing the foot lever 88 move the controlling valve into position to vent the cylinder yof the main actuator, that is by opening valve 4l and valve 43, and by further depressing the foot lever` 88 to bring the collar 29 into contact with the iiange 31 he may then positively move the main actuator piston and apply the brakes connected therewith by his own physical power, so as to prevent an accident which might otherwise occur.y f

We also prefer to provide the portions of the pipes 165 and 9'? on the trailer in rear of the flexible connections 365 and 397 with check valves indicated in Figures 1 and 2 at 267 and 268, re-

spectively. Should the vehicles separate, as by the coupling becoming broken or detached, these check valves will prevent the admission of atmospheric air through the pipes.165 and 97, but the rupture of pipe 98, which will also take place,

which pipe is not provided with a check valve, will permit atmosperlc air to pass into the chamber 92a of the pressure operated device, which will ilex the diaphragm 91B in the direction of the arrow, see Figures 4 and 5, opening the air inlet valve 143 of the auxiliary actuator, and admit atmospheric air to the cylinder in rear of the piston, applying the brakes of the trailer and holding the same applied for a considerable period of time if the cylinder and valves are in proper working condition. Atmospheric air will also be admitted through the portion of the pipe 98 on the tractor to the master actuator cylinder in rear of its piston, applying the tractor brakes momentarily as air will also reach the master cylinder forward of the piston through the pipe 97, which would result in equalizing pressures and releasing the tractor brakes. Air would also be admitted freely to the intake manifold of the engine through the pipe 165 and suction pipe 65, which would interfere to a greater or less extent of the operationof the motor, depending .upon the position of the throttle valve, and this momentary, application of the tractor brakes and interference with the operation of the motor will bring to the attention of the driver of thetractor the fact that something is wrong.

This application is a substitute for abandoned application No. 156,222, led December 21, 1926.

what we claim and desire to secure byLetters Patent isz- -l. The combination with a main .power actuator comprising a cylinder, a double acting piston therein, a main reversing valve mechanism therefor, means for establishing differential pressures on opposite faces of the piston under the control'oi' said reversing valve mechanism, an operator 'operated part connected with said reversing valve mechanism, means for connecting said piston with a part to he operated, an auxilv I fluid pressure operated control device having movable pressure operated portions operatively connected with the said independent valve mechanism of the auxiliary actuator, and pipe connections between said control device and the main actuator cylinder, and between said control device and the auxiliary actuator cylinder, for effecting the operation of said movable portions of the control device and the reversing valve mechanism of the auxiliary actuator by variations of premure within the main and auxiliary actuator cylinders. s

2. The combination with a main power actuator comprising a cylinder, a double acting piston therein, a main controlling and reversing valve therefor, and means for connecting said cylinder with a source of suction and with the atmosphere under the control of said valve m. an operator operated part connected with said valve mechanism, an auxiliary actuator comprising a cylinder, a double acting piston therein, independent controlling and Vreversing .valve mechanism therefor, and means for connecting said cylinder with said source of suction and directly with the atmosphere under the control of said independent valve m, of a fluid pressure operated control device having movablev pressure operated portions operatively connected independent valve m of the auxiliary actuator, and pipe connections said control device andthemain and a tuator cylinders for eii'ecting the operation of said movable portion of the control device and thereversingvalvemechanismoftheauxiliary actuator by variations of pressure within said cylinders. and means for connecting each of said pistons with a part to be actuated.

3. The combination with a main power actuator comprising a cylinder, a double acting piston therein, a main controlling and reversingy valve mechanism therefor, and means for connecting said cylinder with a source of suction and with the atmosphere under the control of said valve mechanism, an operator operated part connected with said valve mechanism, an auxiliary actuator comprising a cylinder, a double acting piston' therein, independent controlling and reversing valve mechanism therefor, and means for connecting said cylinder with said source of suctionand directly with the atmosphere underl the control of said independent valve mechanism, of a fluid pressure operated control device having movable pressure operated portions operatively connected with said independent valve mechanism of the auxiliary actuator, and pipeconnections between said control device and the main and auxiliary actuator cylinders for effecting the operation of said movable portion of the control device and the reversing valve mechanism of the auxiliary actuator by variations of pressure within said cylinders, means for maintaining a connection between the source of suction and each of said cylinders on both sides of the pistons therein when the main. actuator piston is in retracted position, and means for connecting each piston `with a part to be actuated thereby.

v4. The combination with a main power actuator comprising a cylinder, 'a vdouble acting .pistontherein, main reversing valve mechanism therefor, means for connecting said cylinder with a sourceofA suction and vwith the atmosphere under 'the control of said reversing valve mechanism,

said valve mechanism being constructed to connect the portions of the cylinders on both sides of the piston with the source of suctionwhen the piston is in retracted position, to maintain-the piston submerged in vacuum, an operator -operated part connected with said valve mechanism, and means for connecting said piston with a part to be operated, an auxiliary actuator comprising a cylinder, a double acting piston therein, independent reversing valve mechanism therefor, A means for connecting said cylinder directly with said source of suction and the atmosphere under the control of said reversing valve mechanism, of a uid pressure operated control device located adjacent tothe auxiliary actuator, and having retracted position, to connect the portion of the the auxiliary actuator cylinder on both sides of the piston therein with the source of suction, and maintain the auxiliary piston also submerged in vacuum.

5. The combination with a main wpower actuator comprising a cylinder, a double acting piston therein, main reversing valve mechanism therefor, means for connectinglsaid cylinder with a source of suction and with 'the atmosphereunder the control of said reversing valve mechanism, said valve mechanism being constructed to connect the portions of the cylinders on both sides of the piston with the source of suction when the piston is in retracted position, to maintain the piston submerged in vacuum, an operator operseparated chambers, each provided with a prested part connected with said valve mechanism. md means for connecting said piston with a part o be operated, an auxiliary actuator comprising i cylinder, a double acting piston therein, indelendent reversing valve mechanism therefor, neans for connecting said cylinder directly with :aid source of suction and the atmosphere under he control of said reversing valve mechanism, of i fluid pressure operated control device located idjacent to the auxiliary actuator, and having novable pressure operated portions operatively mnnected with said independent reversing valve nechanism thereof, pipe connections between aid control device and the cylinders of the main ind auxiliary actuators for effecting the operaion of the valve mechanism of the auxiliary ictuator, by variations of pressures within said ylinders, said control device being provided with |ypasses for connecting the corresponding ends f said cylinders with each other when the master iston is in retracted position, to maintain` the ,uxiliary actuator piston also submerged in 'acuum, and check valves controlling said bylasses.

6. The combination with a main power actuator omprising a cylinder, a double acting piston herein, a main reversing valve mechanism thereor, means for establishing differential pressures n opposite faces of the piston under the control f said reversing valve mechanism, an operator perated part connected with said reversing valve' mechanism, means for connecting said piston rith a part to be operated, an auxiliary actuator omprising a. cylinder, a double acting piston serein, independent reversing valve mechanism herefor, means for establishing differential presures on opposite faces of said auxiliary piston nder the control of its valve mechanism, means :r connecting the auxiliary actuator piston with part to be operated, of a fluid pressure operted control device having movable pressure operted portions, operatively connected with the alve mechanism for the reversing valve mechaism of the auxiliary actuator, and pipe connec- .onsbetween said control device and the main ctuator cylinder, and between said control device nd the auxiliary actuator cylinder, for effecting :1e operation of said movable portions of the conrol device and the reversing valve mechanism of :1e auxiliary actuator by variations of pressure 'ithin the main and auxiliary actuator cylinders, aid control device being provided with by-passes :r connecting the corresponding portions of said lain and auxiliary actuator cylinders with the )urce of lower pressure independently of the alve mechanism of the auxiliary actuator, and neck valves controlling said by-passes.

7. The combination with a main power actutor comprising a cylinder, a double acting pis- )n therein, a. main reversing valve mechanism ierei'or, means for establishing differential presires on opposite faces of the piston under the Jntrol `of said reversing valve` mechanism, an perator operated part connected with said rearsing valve mechanism, means for connecting iid piston with a part to be operated, an auxiliary ctuator comprising a cylinder, a double acting lston therein, independent reversing valve mechnism therefor, means for establishing differenal pressures on opposite faces of said auxiliary lston under the control of its valve mechanism, .eans for connecting the auxiliary actuator pism with a part to be operated, of a uid presire operated control device provided with two sure operated movable part therein, operatively connected with the reversing valve mechanism y'for the auxiliary actuator, pipe connections from each chamber on opposite sides of the said movable part therein to the corresponding portions of the main and auxiliary actuator cylinders, for

leffecting the operation of the reversing valve mechanism oi' the auxiliary actuator by the operation of the valve mechanism ofthe main actuator under the control of the operator operated part.

8. 'I'he combination with a main power actuator comprising a cylinder, a double acting piston therein, a main reversing valve mechanism therefor, means for establishing differential pressures on opposite faces of the piston under the control of said reversing valve mechanism, an operator operated part connected with said reversing valve mechanism, means for connecting said piston with a part to be operated, an auxiliary actuator comprising a cylinder, a double acting piston therein, independent reversinglvalve mechanism therefor, means for establishing differential pressures on opposite faces of said auxiliary piston under the control of. its valve mechanism, means for connecting the auxiliary'actuator piston with a part to be operated, of a fluid pressure operated control device provided with two separated chambers, each provided with a pressure operated movable part therein, operatively connected with the reversing Valve mechanism for the auxiliary actuator, pipe connections from each chamber on opposite sides of the said movable part therein tothe corresponding portions of the main and auxiliary actuator cylinders, said pipe connections being constructed to effect a movement of the reversing valve mechanism with the auxl iliary actuator in one direction by an increase of pressure in the main actuator cylinder on one side of the piston therein, and to effect the movement of the said valve mechanism in the reverse direction by an increase' of pressure in the main actuator cylinder on the other side o f the piston therein, whereby said main and auxiliary pistons will be substantially simultaneously actuated in either direction under the control of the operatoroperated valve mechanism of the main actuator. l

9. The combination with a main power actuator comprising a cylinder, a double acting piston therein, `a main reversing valve mechanism therefor, means for establishing differential pressures on opposite faces of the piston under the control of said reversing valve mechanism, an operator operated part connected with said reversing valve mechanism, means for connecting said piston with a part to be operated, an auxiliary actuator comprising a cylinder, a double acting piston therein, independent reversing valve mechanism therefor, means for establishing differential pressures on opposite faces of said auxiliary piston under the control of its valve mechanism, means for connecting the auxiliary actuator piston with a part to be operated, of a iiuid pressure operated control device provided with two separated chambers, each provided with a pressure operated movable part therein, operatively connected with the reversing valve mechanism for the auxiliary actuator, pipe connections from each chamber on opposite sides of the said movable part therein to the corresponding portions of the main and auxiliary actuator cylinders, said pressure operated movable parts being co-axial and connected for Joint operation, and said pipe connectionsbeing 8. constructed to eect the movement of -said movable parts and the reversing valve Vmechanism of the auxiliary actuator in one direction by an increase of pressure in the main actuator cylinder on one -side of the piston therein, and in the opposite direction by an increase of pressure in the main actuator cylinder on the other side of the piston therein, whereby the substantially simultaneous operation of both pistons in either direction is controlled by the operator operated valve mechanism of the main actuator.

l0. The combination with a main power actuator comprising a cylinder, a double acting piston therein, a main reversing valve mechanism therefor, means for establishing diil'erential pressures on opposite faces of the piston under the control of said reversingl valve mechanism, an operator operated part connected with said reversing valve mechanism, means for connecting saidpiston with a part to be operated, an auxiliary actuator comprising a cylinder, a double acting piston therein, independent reversing valve mechanism therefor, means for establishing differential pressures on opposite faces of said auxiliary piston under the control of its valve mechanism, means for connecting the auxiliary actuator piston with a part to be operated, of a fluid pressure operated control kdevice provided with two separated chambers,

each provided with a pressure operated movable part therein, operatively connected with the reversing valve mechanism for the auxiliary actuator, pipe connections from each chamber on opposite sides of the said movable part therein tothe corresponding portions oi' the main and auxiliary actuator cylinders, for effecting the operation of the reversing valve mechanism of the auxiliary actuator by the operation of the valve mechanism of the main actuator under the control of the operator -operated part, each chamber of said control device being provided with a by-pass from one side of the movable part therein to the other, for connecting the auxiliary actuator cylinder on opposite sides of'its piston with the source of lower pressure, independently of the valve mechanism of the auxiliary actuator, and a check valve for each oi' said by.

il. The combination with a main power actuator comprising a cylinder, a double acting piston therein, main reversing valve mechanism therefor, means for connecting said cylinder with a source of suction and with the atmosphere under the control of said reversing valve mechanism, said valve mechanism being constructed to connect the portions of the cylinders on both sides ofv the piston with the source of suction when the piston is in retracted position, to maintain the pistonv submerged in vacuum, an operator operated part connected with said valve mechanism, and means for connecting said piston with a part to be operated, an auxiliary actuator comprising a cylinder, a'double acting piston therein, independent reversing valve therefor, means for connectingl said cylinder directly with said source' of suction and the atmosphere under the control of said reversing valve mechanism, of a fluid pressure operated control devicelocated adjacent to the auxiliary actuator and provided with two separated chambers, a pressure operated movable part in each of said chambers. operative- 1y connected with the valve m for the auxiliary actuator, pipe connections between each of said chambers on opposite sides of the movable part therein to the corresponding portions of the main and auxiliary actuator cylinders, to etl'ect the operation of said movable parts and the valve mechanism of the auxiliary actuator by' the-operator controlled valve mechanism oi'lthe main' actuator, each of the chambers of said control device being provided with a ,by-pass from one side of the movable part therein to the other, for connecting the auxiliary actuator cylinder' on both sides of its piston with' the corresponding portions of the main actuator cylinder, independently of the valve mechanism of the auxiliary actuator, and maintain said 'piston also submerged 'in -vacuum when the main actuator pistonis in retracted position, and check valves controlling said by-passes. v, 12.` The combination with a main power actuator comprising a cylinder closed at both ends, a double acting piston in said cylinder, reversing valve mechanism for said actuator, means for connecting said cylinder with a source of suction and with the atmosphere under the control of said valve mechanism, an operator operated part connected with said valve mechanism, and means for connecting said piston4 with a 'part to be` operated, an auxiliary actuator comprising a cylinder closed at both ends, av double actingv piston in said cylinder, controlling valve mechanism for the auxiliary actuator located in the piston thereof, means for connecting said valve mechanism with said source of suction and with the atmosphere, 1a hollow piston rod connected l with said auxiliary actuator piston and extend- .ing through one end of the cylinder thereof, said valve mechanism being constructed to connect the portion of the auxiliary actuator cylinder on one side of the piston with the source of l suction, and the portion on the opposite side of the piston with the atmosphere, and to reverse said connections, of a fluid pressure operated control de'vice carried by said hollow piston rod and movable therewith, and provided with two 1 co-axial separate pressure chambers, a movable pressure operatedv part in each chamber, a valve operating device connecting said movable parts with said reversing valve mechanism for operating the same, pipe connections from each of said l chambers on opposite sides of the movable pressure operated part therein to corresponding por-` tions of the main and auxiliary actuator cylinders, to eifect the operation of said movable parts and the valve mechanism or the auxiliary actuator by the operator controlled valve mechanism of the main actuator, and means for vconnecting the auxiliary pistonA with a part to be operated.

13. The combination with a main power actuator comprising a cylinder closed at both ends, a double acting piston in said cylinder, reversing valve mechanism for said actuator, means for connecting said cylinder' with a source of suction and with .the atmosphere under the control of said valve mechanism, an operator operated part connected with saidlvalve mechanism, and means for connecting saidpiston with a part to be operated, an auxiliary actuator comprising a cylinder closed at both ends, a double acting piston in said cylinder, controlling valve mechanism for the auxiliary actuator located in the piston thereof, means for connecting said valve mechanism with said source of suction and with the atmosphere, hollow piston rods connected with said auxiliary actuator piston and extending through 1 the ends of the cylinder thereof, said valve mechanism being constructed to connect the portion o! the auxiliary actuator cylinder on one sideof the piston with the source of suction, and the portion on the opposite side of the piston with the 1` atmosphere, and to reverse said connections, o! a fluid pressure operated control device carried by one of said hollow piston rods and movable therewith, and provided with two co-axial separate pressure chambers, a movable pressure operated part in each chamber, a valve operating device connecting said movable parts with said reversing valve mechanism for operating the same, pipe connections from each of said chambers on opposite sides of the pressure operated part therein to corresponding portions of the main and auxiliary actuator cylinders, to effect the operationY of said movable parts and the valve mechanism of the auxiliary actuator by the operator controlled valve mechanism of the main actuator, each of said chambers being provided with a bypass for connecting the portions thereof on opposite sides of the pressure operated part therein, and a check valve for each of said by-passes.

14. The combination with a main power actuator comprising a cylinder closed at both ends, a double acting piston in said cylinder, reversing valve mechanism for said actuator, means for connecting said cylinder with a. source of suction and with the atmosphere/under the control of said valve mechanism, an operator operated part connected with said valve mechanism, and means for connecting said piston with'a part to be operated, an auxiliary actuator comprising a cylinder closed at both ends, a double acting piston in said cylinder, controlling valve mechanism for the auxiliary actuator located in the piston thereof, means for connecting said valve mechanism with said source of suction and with the atmosphere, hollow piston rods connected with said auxiliary actuator piston and extending throughl the ends o f the cylinder thereof, said valve mechanism being constructed to connect the portion of the auxiliary actuator cylinder on one side of the piston with the source of suction, and the portion on the opposite side of the piston with the atmosphere, and to reverse said connections, a fluid pressure operated control device carried by one o f said hollow piston rods and movable therewith, and provided with two co-axial separate pressure chambers, a movable pressure operated part in each chamber, a valve operating device connecting said movable parts` with said reversing valve mechanism for operating the same, pipe connections from each of said chambers on opposite sides of the movable pressure operated part therein to corresponding portions of the main and auxiliary actuator cylinders, the valve mechanism of the main actuator being constructed to connect the portions of the main actuator cylinder on opposite sides of the piston therein with the source of suction when the said piston is in retracted position, to maintain the said piston normally submerged in vacuum, said control device having each chamber thereof provided with a by-pass for connecting the portions of each chamber on opposite sides of the movable pressure operated part therein, with the source of suction when the main actuator piston is in the retracted position. to `place each end portion of the auxiliary actuator cylinder in communication with the corresponding portion of the main actuator cylinder and with the source of suction, and maintain the auxiliary actuator piston also submerged in vacuum, and a check valve for eachv of said by-passes.

15, In brake mechanism for automotive vehicles providedwith independently operable brake mechanisms, the combination with a main power actuator comprising a cylinder, a double acting piston thexein, a main reversing valve mechanism therefonmeans for establishing diierential pressures on opposite faces of the piston under the 'control of said reversing valve mechanism, an operator operated part connected with said reversing valve mechanism, means for connecting said piston with certain of said brake mechanisms, an auxiliary actuator comprising a cylinder, a double acting piston therein, independent reversing valve mechanism therefor, means for establishing differential pressures on opposite faces of said auxiliary actuator. piston under the control of its valve mechanism, and means forconnecting the auxiliary actuator piston with certain of said brake mechanisms, oi' a fluid pressure operated control device having movable pressure operated `portions operatively connected with the said independent valve mechanism of the auxiliary actuator, and pipe connections between said control device and the main actuator cylinder, andrbetween said control device and the auxiliary actuator cylinder, for efiecting the operation of said movable portions of the control device vand the reversing valve mechanism of the auxiliary actuator by variations of pressure within the main and auxiliary actuator cylinders, and a connection between said operator operated part and the brake mechanism connected with the main actuator piston, for enabling the operator to add his physical force to that of the main actuator and to actuate said brake mechanism by his physical force alone in case of failure of power.

16. In a brake system for automotive vehicles propelled by an internal combustion engine hav- 'ing a suction passage, and provided with independently operable brake mechanism, the combination with a main power actuator comprising a cylinder, a double acting piston therein, controlling and reversing valve mechanism, and means for connecting the cylinder with the suction passage of the engine and with the atmospherennder the control of said valve mechanism, an operator operatedpart connected with said valve mechanism, and connections between said piston andcertain of said brake mechanism, an auxiliary power actuator comprising a cylinder, a double acting piston therein, independent controlling and reversing valve mechanism, and means for connecting said auxiliary actuator cylinder with said suction passage and directly with the atmosphere independently of the main actuator, under the control of said independent valve mechanism, and connections between said auxiliary actuator piston and other oi' said brake mechanism, of a fluid pressure operated control device located adjacent to said auxiliary actuator, and having movable pressure operated portions operatively connected with said independent valve mechanism of the auxiliary actuator, and pipe connections between said control device and the cylinders of the actuators, whereby the pistons of both actuators and the brake mechanisms connected therewith may be substantially simultaneously actuated in both directions under the control of the operator operated valve mechanism of the main actuator.

17. In a brake system for automotive vehicles provelled by an internal combustion engine having a suction passage, and provided with independently operable brake mechanism, the combilnation with a main power actuator comprising a the control of said valve mechanism, an operator operated part connected with said valve mechanism, and connections between said piston and certain of said brake mechanism, an auxiliary power actuator comprising a cylinder, a double acting piston therein; independent controlling and reversing valve mechanism, and means' for connecting said auxiliary actuator cylinder with said suction passage and directly with the atmosphere independently of the main actuator, under the control of said independent valve mechanism, and connections between said auxiliary actuator piston and other of said brake mechanism, of a uid pressure operated control device located adjacent to said auxiliary actuator, and having movable pressure operated portions operatively connected with said independent valve mechanism of the auxiliary actuator, and pipe connections between said control device and the cylinders of the actuators, whereby the pistons of both actuators and the brake mechanisms connected therewith may be substantially simultaneously actuated in both directions under the control of theoperator operated valve mechanism of the main actuator, and connections between the operator operated part and the brake mechanism connected with the main actuator piston, containing a provision for lost motion sucient to insure the operation of the valve mechanism connected'with the operator operated part, whereby the physical force of the operator may be added to that of the main actuator, and the brake mechanism connected with the main actuator piston may be operated by the physical force-of the operator alone in case of failure of power. y

18. In brake mechanism for a main automotive vehicle provided with an internal combustion engine having a suction passage, and brake mechanism for-the vehicle, anda trailer propelled by the main vehicle and provided with independently operable brake mechanism, the combination with a main power actuator located on the main vehicle and comprising a cylinder, a double acting piston therein, controlling and Vreversing valve mechanism, and means for connecting the cylinder with said suction passage and with the atmosphere under the control of said valve mechanism, connections between the main actuator piston and brake mechanism for the main vehicle..

an operator operated part on the main vehicle connected with said valve mechanism, an auxilviary actuator carried by the trailer comprising a cylinder, a double acting piston, independent controlling and reversing valve mechanism, and means for connecting the auxiliary actuator cylinder with the saidsuction passage of the engine and directly with the atmosphere under the control of said independent valve mechanism, and means for connecting the auxiliary actuator piston with brake mechanism-for the trailer, of a fluid pressure operated control device on said trailer having movable pressure operated portions connected with said independent valve mechanism, and pipe connections from said control device to the main and auxiliary actuator cylinders for operating the valve mechanism of the auxiliary actuator by variations of pressures within the said actuator cylinders, whereby the brake mechanism of the main vehicle and trailer may be substantially simultaneously applied and released under the control of the operator operated valve mechanism of the main actuator.

19. In a brake system for a main automotive vehicle provided with an internal combustion engine having a suction passage, and brake mechanism for the vehicle, and a trailer propelled by the mainvehicle and provided with independently operable brake mechanism, the combination with a main power actuator located on the main vehicle and comprising a cylinder, a double actng piston therein, controlling and reversing valve mechanism, and means for connecting the cylinder with said suction passage and with the atmosphere under the control of said valve mechanism, connections between the main actuator pist0n andbrake mechanism for the main vehicle, an operator operated part on the main vehicle connected with said valve mechanism, an auxiliaryI actuator carried by' the trailer comprising a cylinder, a double acting piston, independent controlling and reversing valve mechanism,Y and means for connecting the auxiliary actuator cylinder with the said suction passage of the engine.

and directly'with the atmosphere under the control of said independent Ivalve mechanism, and

means for connecting the auxiliary actuator pist0n with brake mechanism for the trailer, of a fluid pressure operated control device on said trailer having movable pressure operated portions connected with said independent valve mechanism, and pipe connections from said control device to the main and auxiliary actuator cylinders for operating the valve mechanism of the auxiliary actuator by variations of pressures within the said actuator cylinders, whereby the brake mechanism ofthe main vehicle and trailer may be substantially simultaneously applied and released under the control of the operator operated valve mechanism of the main actuator, and connections between the operator operated part and brake mechanism for the main vehicle connected with the main actuator piston, having a provision for lost motion suflicient to operate the main actuator valve mechanism,]

whereby the operator may add his physical force tothe brake mechanism of the main vehicle in addition to that of thenactuator and may apply the brake mechanism of the main vehicle by physical force alone in case of failure oi' power.

20. In a brake system for a main automotive vehicle provided with an internal combustion engine having a suction passage, and brake mechanism for the vehicle, and a trailerI propelled by the main vehicle and provided with independently operable brake mechanism, the combination with a main power actuator located on the mainl vehicle and comprising a cylinder, a double acting piston therein, controlling and reversing valve mechanism, and means for connecting the cylinder with said suction passage and with the atmosphere under the control of said valve mechanism, connections between the main actuator piston and brake mechanism for the main vehicle, an operator operated `part on the main vehicle connected with said valve mechanism, an auxiliary actuator carried by the trailer comprising a cylinder, a double acting-piston, independent controlling and reversing valve mechanism, and means for connecting the auxiliary actuator cylinder with the said suction passage of the engine and directly with the atmosphere under the control of said independent valve mechanism, and means for connecting. the auxiliary actuator piston with brake mechanism for th'e trailer, of a fluid pressure operated control device on said trailer provided with two chambers, co-axial pressure operated movable parts, each interposed between portions of one of said chambers, connections from said movable parts to the valve mechanism of the auxiliary actuator, pipe connections from each chamber on opposite sides of the movable part therein to corresponding portions of the main and auxiliary actuator cylinders, whereby the brake mechanism for the main vehicle and trailer may be substantially simultaneously applied and released under the control of the operator operated valve mechanismof the main actuator.

21. In a brake system for a main automotive vehicle provided with an internal combustion engine having a suction passage, and brake mechanism for the vehicle, and a trailer propelled by the main vehicle and provided with independently operable brake mechanism, the combination with a main power actuator located on the main vehicle and comprising a cylinder, a double acting piston therein, controlling and reversing valve mechanism, and means for connecting the cylinder with said suction passage and with the atmosphere under the control of said valve mechanism, connections between the main actuator piston and brake mechanism for the main vehicle, an operator operated part on the main vehicle connected with said valve mechanism, an auxiliary actuator carried by the trailer comprising a cylinder, a double acting piston, independent controlling and reversing valve mechanism, and means for connecting the auxiliary actuator cylinder with the said suction passage oi the engine and directly with the atmosphere under the control of said independent valve mechanism, and means for connecting the auxiliary actuator piston with brake mechanism for the trailer, of a uid pressure operated control device on said trailer provided with two chambers, co-axial pressure operated movable parts, each interposed between portions of one of said chambers, connections from said movable parts to the valve mechanism of the auxiliary actuator, pipe connections from each chamber on opposite sides of the movable part therein to corresponding portions oi the main and auxiliary actuator cylinders, xeach of said chambers being provided with a by-pass connecting the portions thereof on opposite sides of the pressure operated part therein, and a check valve for each of said by-passes.

22. In a brake system for a main automotive vehicle provided with an internal combustion engine having a suction passage, and brake mechanism for the vehicle, and a trailer propelled by the main vehicle and provided with independently operable b rake mechanism, the combination with a main power actuator located on the main vehicle and comprising a cylinder, a double acting piston therein, controlling and reversing valve mechanism, and means for connecting the cylinder with said suction passage and with the atmosphere under the control of said valve mechanism, connections between tne main actuator piston and brake mechanism for the main vehicle, an operator operated part on the main vehicle connected with said valve mechanism, an auxiliary actuator carried by the trailer comprising a cylinder, a double acting piston, indepedent controlling and reversing valve mechanism. and means for connecting ,the auxiliary' actuator cylinder with the said suction passage of the engine and directly with the atmosphere under the control of said independent valve mechanism, and means for connecting the auxiliary actuator piston withbrake mechanism for the trailer, of a fluid pressure operated control device on said trailer provided with two chambers, pressure operated movable parts, each interposed between portions of one of vsaid chambers, connections from said movable parts to the valve mechanism of the auxiliary actuator, pipe connections from each chamber on opposite sides o! the movable part therein to corresponding portions of the main and auxiliary actuator cylinders, the main actuator being provided with means for maintaining its cylinder on both sides of the piston therein in communication with the suction passage of the engine when the piston is in retracted position, and the chambers of said control device being each provided with a by-pass connecting the portions thereof on opposite sides of the movable part therein, and check valves for said by-passes adapted to open in a direction toward the portion of the chamber connected with the main actuator, whereby the auxiliary actuator cylinder on both sides of the piston will be connected with the suction passage of the engine j `vhen the main actuator piston is in retracted position.

23. In a brake system for a main automotive vehicle provided with an internal combustion engine having a suction passage, and brake mechanism for the vehicle, and a trailer propelled by the main vehicle and provided with independently operable brake mechanism, the combination with a main power actuator located on the main vehicle and comprising a cylinder, a double acting piston therein, controlling and reversing valve mechanism, and means for connecting the cylinder with said suction passage and with the atmosphere under the control oi' said valve mechanism, connections between the main actuator piston and brake mechanism for the main vehicle, an operator operated part on the main vehicle connected with said valve mechanism, an auxiliary actuator carried by the trailer comprising a cylinder, a double acting piston, independcylinder with the said suction passage of the en- A gine and directly with the atmosphere under the control of said independent valve mechanism,

and means for connecting the auxiliary actuator piston with brake mechanism for the trailer, of a iluid pressure operated control device on said trailer provided with two chambers, co-axial pressure operated movable parts, each interposed between portions of one of said chambers. connections from said movable parts to the valve mechanism oi' the auxiliary actuator, pipe connections from each chamber on opposite sides of the movable part therein to corresponding portions of the main and auxiliary actuator cylinders,\ the main actuator being provided with means for maintaining its cylinder on-both sides of the piston therein in communication with the suction passage of the engine when the piston is in retracted position, and the chambers o1 said control device being each provided with a by-pass connecting the portions thereof on opposite sides of the movable part therein, and check valves for said by-passes adapted to open in a direction toward the portion ot the chamber connected with the main actuator, whereby the auxiliary actuator cylinder on bothV sides of the piston will be connected with the suction e of the en- .gine when the main actuator piston is in retracted position, and check valves on the trailer in the pipe connections between the auxiliary actuator valve mechanism and the suction passage or' the engine, and between the control device and the main actuator cylinder forward o! the piston therein, and irangible portions in said pipes between said check valves and the main vehicle, whereby in case the trailer breaks away from the main vehicle said check valves will maintain ratification in the auxiliary actuator cylinder forward of the piston, auxiliary actuator cylinder forward of the piston and in the control device, and whereby the admission of atmospheric air, through the broken pipe connection between the main actuator cylinder in rear of the piston therein and the control device, would automatically operate the valve mechanism of the auxiliary actuator to apply the trailer brakes.

24. In a brake system for automotive vehicles provided with an internal combustion engine having a suction passage, and independently operable brakemechanisms, the combination with a main and an auxiliary power actuator, each comprising a cylinder, 'a double acting piston therein, and controlling and reversing valve mechanism therefor, means for connecting each of said pistons with certain of said brake mechanisms, means for connecting each of said cylinders under the control of the valve mechanism therefor with said suction passage and with the atmosphere, of a pressure operated control device adjacent to the auxiliary actuator provided with movable portions operatively connected with the valve mechanism for the auxiliary actuator, and connections between said control device and the main and auxiliary actuator cylinders, said/control device/being constructed to normally maintain the auxiliary actuator cylinder on both sides of the piston therein, in communication with said suction passage and said piston submerged in vacuum, and to effect a power stroke of the auxiliary actuator piston to apply the brakes connected therewith under the control of the valve mechanism for the main actuator without delivering appreciable quantities of air from the auxiliary actuator cylinder to said suction passage, and an operator operated device connected with the valve mechanism for the main actuator.

25. In a brake system for automotive vehicles having an internal combustion engine provided with a suction passage, and independently operable brake ,mechanisma the combination with a main and an auxiliary power actuator, each comprising a cylinder, a double acting piston therein, and controlling and reversing valve mechanism, an operator operated vpart connected withrthe valve mechanism of the main actuator, and connections from each pistonl to certain of said brake mechanisms, the valve mechanism of ther main actuator being constructed to connect the main actuator cylinder on both sides of the piston therein with said suction passage when said piston is in retracted position, of a pressure operated control -device adjacent to the auxiliary actuator provided with mov- 26. In combination, main and auxiliary actuators, each including a cylinder and a double f acting piston, means connecting the pistons of said actuators with parts to be operated, valve mechanism for each of said actuators adapted to control higher and lower pressures to either l side of the pistons in said cylinder, a control device operatively connected with the valve mechanism of the auxiliary actuator, and fluid connections between said actuators for effecting the `operation of the valve mechanism of the auxiliary actuator through the operation of the control device by variations of pressure within the main and auxiliary cylinders.

27. In combination, main and auxiliary actuators, each including a cylinder and a double acting piston operating therein, means connecting the pistons and the actuators with parts to be operated control valve mechanism for each of said actuators adapted to control higher and lower pressures to either side of the pistons in said cylinders, a control device operatively connected with the valve mechanism of one of the actuators, and vfluid connections between said actuators for effecting the operation of the valve mechanism of the actuator with which the control device is associated through the operation of said control device by variation of pressure within the main and auxiliary cylinders.

28. In combination, main Jand auxiliary actuators, each including a cylinder and a double acting piston operating therein, means connecting the pistons of said actuators with parts to be operated, valve mechanism for each of said actuators located within the pistons of said Iactuators and adapted to control higher and lower pressures to either side of the pistons in said cylinders, and a control device operatively connected with the valve mechanism of one of the actuators and connected to the other actuator for effecting the operation of the valve mechanism of the 'actuator with which it is associated through variation of pressures in the main and auxiliary cylinders.

CALEB S. BRAGG. VICTOR W. KLIESRA'I'H. 

